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Aug. 14, 1923. 1,464,533

` s. LOEWE RADIO-lECEIVIG SYSTBI Y Filed Aug. s. 1521.

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Patented Aug. 1A 1923. 1,464,533

UNITED STATES PATENT' OFFICE.

BIEGMUND LOEWE, F IIBBLIN, GERMANY.

RADIO RECEIVING SYSTEM.

Application nled August 26, 1921. Serial No. 495,778.

put circuit includes the entire electrical path between filament and grid. In this output circuit there is connected the primary 6 of an amplifying transformer the seconderr of which is connected to the grid of nn amplifier tube 11. The primary 6 of this trans- 5G former is conductively connected to the secondary 7 to avoid local oscillations in the circuit. ln order to make this possible without short eircuiting the local source of energy 3, there is provided, according to this invention, a condenser 13 which is inserted in series with the primary windinf.r ll. The primary 8 and the secondary 9 of the succeedinp; transformer are connected in the usual nnmner to the various circuits, und the telephone or other indicator 10 is placed in the output circuit of the amplifier tube 12.

lt is to be understood. howeve that the foregoing disclosure is intended merely as an illustration of one embodiment of the present invention, und is to in no way limit the spirit or scope of this invention.

I claim:

1. In o radio receiving,y system comprising a vacuum tube detector having input. und 00 output circuits und o. vacuum tube amplifier havin;r input and output circuits: menus for operatively connecting the input circuit of Suid amplilier to the output circuit of said detector comprising.;v :l trmisfornur the pri- 35 murv :ind secondary windings of which ure conduclivcly connected together, und u coudcnser in .series with Huid trunsformcr priv mary.

2. ln u rudio receiving system com prisii c: 9U an antenne, a vucuum tube detector having nu input circuit coupled to Suid :interino and un output. circuit including u source of cnergy :1nd thc primary of u transformer. und a vacuum tube fumplilier havingv :1n output 95 circuit including :in indicator und :in input circuit including the secondo ry ol' Suid trous Be it known that I, SIEGMUND LOEWE, a subect of the State of Germany, residing at 69 Jtromstrasse, Berlin NW, Germany, have invented certain new and useful Improvements in Rudio Receiving Systems (for which application has been made in the fol lowing countries: Germany, Apr. 18, 1918; Sweden, June 29, 1920, Patent No. 3,574; Great Britain, July 12, 1920, Pat/ent No. 20,965; Holland, July'12, 1920, Patent'No. 15,557; France, July 30, 1920, Patent-No. 132,041; Czechoslovakia, July, 1920, Patent No. 12,745; Switzerland, 1921), of which the following is a specification.

It has been found in the operation of nudion receivers which utilize vacuum tube amplifiers that there is apt to be present a' local oscillation in one or more of the various circuits and that. it is extremely dillicult to avoid these oscillations. Even in multistage amplifiers which do not use an audion or n vacuum tuhe detector, the local oscillation could he prevented only by conduetvely connecting the primary and secondary of the amplifying transformer. Heretofore this procedure has not been adopted when audion detectors were employed, as such a connection would short circuit one of the audion batteries.

lt is the object. of this invention, therefore, to provide n circuit und connections whereby multistage amplifiers muy he used in conjunction with vacuum tuhc detectors and the local oscillations may he eliminated by conduclively connectingr the primary and seci ondnry windings of the first stage trunsformer.

In the accompanying! drawingr there is shown one of many forms of circuits to which my invention is applicable. In the circuit illustrulcd there is employed a vacum tuhe detector und n two-stage ampli- Iier. ullhougrh. of course, it is lo be understood IlunY :is unlny stages of umplification muy he added :1s desired.

le this drnwing there is shown u vacuum' tuludetector I hnvintr its pluto connected to the nntennu 5 und its grid connected in lhe output circuit which includes the resonant. circuit i :md the local source of energy 3. The filament of-lhe vacuum tube muy be lrcflted hy menus of u buttery 2. i

ft is to he understood that the grid or outformer, said Lrziusl'ogner primary und scc ondary beingr conductivelv connected toi gethcr; means for preveutlmr the short cirm0 cultof said source of energy through seid transformer comprising u stoppincr com denser in series with Suid transformer pri mary.

3. In u, rudio receiving system comprising u vacuum tube detector having: un input cin cult and un output circuit including a source of energy and the prnunry of utronsformcr,

and a vacuum tube amplier having an output circuit and an input circuit including the secondary of said transformer; means for preventirnf,r the local oscillations of said 5 receiving system comprising a conductive connection between the primary and secondary of said transformer, and a condenser in series with the primary of said transformen to, prevent the short circuit of said sou'ce of energy through said transformer'.

In testimon whereof I affix my signature in presence o two witnegses. i

DR. SIEGMU!) LQEWE, Witnesses Dr. ElueH GEINLER. Dr.F WALBY. 

